The invention relates to a system, device and method for providing call forwarding in dual subscription to different types of networks, e.g. a packet-based and circuit-switched network.
More specifically, the invention relates, according to some of the embodiments, to 3GPP (Third Generation Partnership Project) IP (Internet Protocol) Multimedia network, and to call control, e.g. using a HSS (Home Subscriber Server) or Call Processing Server (CPS).
When considering to enable roaming of a user equipment between networks of different types, e.g. between an IMS (IMS; IP Multimedia Subsystem) and a CS (Circuit-Switched) network, by providing two subscriptions, problems may arise. First, if both subscriptions are unregistered and CS or IMS network receives a call, a forwarding loop may be built: e.g. CS→IMS→CS→IMS→ etc until the network detects and interrupts the loop. Second, if a service such as “Call forwarding on mobile not reachable” contains on both sides (IMS and CS) a routing number to another side, it is not possible to route the call e.g. to voice mail at all in “not reachable” case.